St. Augustine Grass Care Guide
St. Augustine is the go-to warm-season grass for the Gulf Coast, Florida, and parts of the Southeast. It offers the best shade tolerance of any warm-season grass and produces a thick, lush lawn — but it is not available from seed (sod or plugs only).
Mowing
Maintain St. Augustine at 3-4 inches — the highest mowing height of any warm-season grass. This helps shade the soil, retain moisture, and suppress weeds. Never remove more than one-third of the blade length in a single mowing.
Fertilization
St. Augustine needs 2-4 lbs N per 1,000 sq ft per year. Apply starter at greenup (soil 65°F+), then 0.5-1 lb N every 6-8 weeks during active growth. Iron applications can enhance color without excessive growth.
Chinch Bugs
Chinch bugs are the #1 pest for St. Augustine, especially during hot, dry summer conditions. They suck plant juices and inject a toxin that kills the grass. Look for irregular yellow-brown patches that expand outward. Treat with bifenthrin when damage appears.
Take-All Root Rot
TARR is a fungal disease specific to St. Augustine in zones 8-10 that attacks during spring wet conditions. Preventive azoxystrobin plus peat moss top-dressing is the standard treatment protocol.
Weed Control
Atrazine is the standard broadleaf herbicide for St. Augustine. It is safe at label rates and handles most common weeds. For sedges, use SedgeHammer (halosulfuron). Avoid MSMA and organic arsenicals.
Recommended Products for St. Augustine
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Trichlorfon (Dylox)
Curative grub control — kills active grub infestations within 24 hours
$25-40 per bag
Imazaquin
Nutsedge, crabgrass, and broadleaf weeds in warm-season lawns
$15-25 per bottle
Fipronil
Mole cricket control in warm-season lawns (zones 8-10). Also effective on fire ants.
$30-50 per bag
Humic acid 55% concentrate
Soil health improvement, nutrient uptake enhancement, microbial activity support
$25-40 per lb
Dithiopyr 24%
Split-app first pass, late starters, or anyone planning fall overseeding
$160 for 64 oz
24-0-6 (slow-release nitrogen + potassium)
Spring and fall fertilization for cool-season lawns. Slow-release nitrogen with light potassium.
$30-50 per 50 lb bag